1. Field of the Invention
The present invention relates to a method for manufacturing a ceramic multi-layered substrate. In particular, the present invention relates to a method for manufacturing a ceramic multi-layered substrate including a plurality of stacked ceramic layers.
2. Description of the Related Art
Ceramic multi-layered substrates including a plurality of stacked ceramic layers can be efficiently produced by simultaneously firing a source substrate including a plurality of ceramic multi-layered substrates and cutting the source substrate into individual ceramic multi-layered substrates after firing.
For example, Japanese Unexamined Utility Model Registration Application Publication No. 4-38071 discloses that ceramic green sheets having dividing lines are transferred and laminated to form a laminate, dividing grooves are formed by, for example, irradiating the dividing lines with a CO2 laser after the laminate is subjected to heat treatment, and the laminate is separated into many substrates.
Japanese Unexamined Patent Application Publication No. 5-75262 discloses that dividing grooves are formed in advance in either or both of front and back surfaces of press-bonded ceramic green sheets, and the substrate is bent to form cracks along the dividing grooves after heat treatment, thereby separating the substrate into many substrates.
Japanese Unexamined Patent Application Publication No. 2001-332857 discloses a ceramic substrate having cavities therein that is formed by laminating ceramic green sheets having depressions formed by performing pressing partway into the sheets.
Japanese Unexamined Patent Application Publication No. 2005-311225 discloses that ceramic green sheets each having a shape corresponding to the outer shape of a laminated electronic component are laminated, removable material layers are laminated at locations corresponding to cutting margins, and the removable material layers are removed after firing, thereby separating the laminate into individual laminated electronic components.
In Japanese Unexamined Utility Model Registration Application Publication No. 4-38071, however, an expensive, large-scale CO2 laser irradiation apparatus is required. The laser irradiation requires a long time. During cutting, the substrates may be broken by thermal stress, and deformation and/or alteration due to the heat of the laser may occur at and around sections of the substrate.
In the method disclosed in Japanese Unexamined Patent Application Publication No. 5-75262, failures, such as deformation and breakage, may occur in the press-bonded sheets during conveyance due to the dividing grooves. When the heat-treated substrate is bent, the substrate may be broken at undesired locations other than the grooves, which results in defective articles. Although the substrate is separated along the dividing grooves, sections may have irregular shapes, which results in out-of-specification products.
In the method disclosed in Japanese Unexamined Patent Application Publication No. 2001-332857, the cavities may collapse or be deformed due to the uneven thickness of the ceramic green sheets and uneven pressing force. Thus, it is difficult to accurately form cavities.
In the method disclosed in Japanese Unexamined Patent Application Publication No. 2005-311225, it is necessary to prepare the ceramic green sheets into which the removable material is charged such that the sheets have a shape corresponding to the outside shape of the laminated electronic component, which results in a complicated production process. After firing, the laminate is separated into individual components. For example, to perform a step of mounting surface-mounted components thereon, the individual components must be rearranged.